A Spartan warrior who fought at the Battle of Thermopylae in 480 BC. Remembered in the Histories of Herodotus for one glib remark that illustrates the Spartan ethos well.
The following is book 7, chapter 226 of the Histories:
<clears throat and takes a deep breath>
Lakedaimoniôn de kai Thespieôn toioutôn genomenôn homôs legetai anêr aristos genesthai Spartiêtês Diênekês: ton tode phasi eipein to epos prin ê summixai spheas toisi Mêdoisi, puthomenon pros teu tôn Trêchiniôn hôs epean hoi barbaroi apiôsi ta toxeumata, ton hêlion hupo tou plêtheos tôn oistôn apokruptousi: tosouto plêthos autôn einai. ton de ouk ekplagenta toutoisi eipein en alogiêi poieumenon to Mêdôn plêthos, hôs panta sphi agatha ho Trêchinios xeinos angelloi, ei apokruptontôn tôn Mêdôn ton hêlion hupo skiêi esoito pros autous hê machê kai ouk en hêliôi.
(This then is how the Lacedaemonians and Thespians conducted themselves, but the Spartan Dienekes is said to have exhibited the greatest courage of all. They say that he made the following speech before they joined battle with the Medes: he had learned from a Trachinian that there were so many of the barbarians that when they shot their missiles, the sun was hidden by the multitude of their arrows. He was not at all disturbed by this and made light of the multitude of the Medes, saying that their Trachinian foreigner brought them good news. If the Medes hid the sun, they could fight them in the shade instead of in the sun. This saying and others like it, they claim, Dienekes the Lacedaemonian left behind as a memorial.)